{"title":"考虑元素尺寸影响的改进型钢连接延性断裂模型的数值模拟","authors":"","doi":"10.1016/j.jcsr.2024.109031","DOIUrl":null,"url":null,"abstract":"<div><p>Crack initiation and propagation behaviors are the dominant characteristics of ductile fracture for structural steels. This study aims to predict the strength degradation of steel connections caused by ductile crack and the effect of element size in FE simulation. Tensile fracture tests were conducted on notched specimens to study the crack behavior of structural steel. An improved micromechanics-based fracture model which considers crack initiation and propagation was proposed, and the parameters involved in the model were calibrated. The micro void growth and coalescence inside the material were numerically investigated using the void-cell model. The fracture process of bolted connections under tension was studied with the aid of the proposed model. Results show that a higher stress triaxiality leads to an increase in the yield and ultimate strengths. The proposed fracture model is applicable to different element sizes of numerical models, and its effectiveness was verified by the experimental results. Stress triaxiality has a great influence on the micro void grow rate, and the void grows faster at a higher stress triaxiality state. The ductile fracture process of bolted connections can be predicted very well using the proposed model. For the multi-bolt connection, the load carrying capacity decreases as the load angle increases.</p></div>","PeriodicalId":15557,"journal":{"name":"Journal of Constructional Steel Research","volume":null,"pages":null},"PeriodicalIF":4.0000,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Numerical simulation with an improved ductile fracture model for steel connections considering effect of element size\",\"authors\":\"\",\"doi\":\"10.1016/j.jcsr.2024.109031\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Crack initiation and propagation behaviors are the dominant characteristics of ductile fracture for structural steels. This study aims to predict the strength degradation of steel connections caused by ductile crack and the effect of element size in FE simulation. Tensile fracture tests were conducted on notched specimens to study the crack behavior of structural steel. An improved micromechanics-based fracture model which considers crack initiation and propagation was proposed, and the parameters involved in the model were calibrated. The micro void growth and coalescence inside the material were numerically investigated using the void-cell model. The fracture process of bolted connections under tension was studied with the aid of the proposed model. Results show that a higher stress triaxiality leads to an increase in the yield and ultimate strengths. The proposed fracture model is applicable to different element sizes of numerical models, and its effectiveness was verified by the experimental results. Stress triaxiality has a great influence on the micro void grow rate, and the void grows faster at a higher stress triaxiality state. The ductile fracture process of bolted connections can be predicted very well using the proposed model. For the multi-bolt connection, the load carrying capacity decreases as the load angle increases.</p></div>\",\"PeriodicalId\":15557,\"journal\":{\"name\":\"Journal of Constructional Steel Research\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":4.0000,\"publicationDate\":\"2024-09-17\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Constructional Steel Research\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0143974X24005819\",\"RegionNum\":2,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"CONSTRUCTION & BUILDING TECHNOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Constructional Steel Research","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0143974X24005819","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CONSTRUCTION & BUILDING TECHNOLOGY","Score":null,"Total":0}
引用次数: 0
摘要
裂纹的起始和扩展行为是结构钢韧性断裂的主要特征。本研究旨在预测延性裂纹引起的钢连接强度下降以及 FE 模拟中元素尺寸的影响。对缺口试样进行了拉伸断裂试验,以研究结构钢的裂纹行为。提出了一种基于微观力学的改进断裂模型,该模型考虑了裂纹的起始和扩展,并对模型中的相关参数进行了校准。利用空穴模型对材料内部的微空隙生长和凝聚进行了数值研究。借助所提出的模型,研究了螺栓连接在拉力作用下的断裂过程。结果表明,三轴应力越大,屈服强度和极限强度越高。所提出的断裂模型适用于不同元素尺寸的数值模型,其有效性得到了实验结果的验证。应力三轴度对微观空隙增长速率有很大影响,应力三轴度越大,空隙增长越快。利用提出的模型可以很好地预测螺栓连接的韧性断裂过程。对于多螺栓连接,承载能力随着荷载角的增大而减小。
Numerical simulation with an improved ductile fracture model for steel connections considering effect of element size
Crack initiation and propagation behaviors are the dominant characteristics of ductile fracture for structural steels. This study aims to predict the strength degradation of steel connections caused by ductile crack and the effect of element size in FE simulation. Tensile fracture tests were conducted on notched specimens to study the crack behavior of structural steel. An improved micromechanics-based fracture model which considers crack initiation and propagation was proposed, and the parameters involved in the model were calibrated. The micro void growth and coalescence inside the material were numerically investigated using the void-cell model. The fracture process of bolted connections under tension was studied with the aid of the proposed model. Results show that a higher stress triaxiality leads to an increase in the yield and ultimate strengths. The proposed fracture model is applicable to different element sizes of numerical models, and its effectiveness was verified by the experimental results. Stress triaxiality has a great influence on the micro void grow rate, and the void grows faster at a higher stress triaxiality state. The ductile fracture process of bolted connections can be predicted very well using the proposed model. For the multi-bolt connection, the load carrying capacity decreases as the load angle increases.
期刊介绍:
The Journal of Constructional Steel Research provides an international forum for the presentation and discussion of the latest developments in structural steel research and their applications. It is aimed not only at researchers but also at those likely to be most affected by research results, i.e. designers and fabricators. Original papers of a high standard dealing with all aspects of steel research including theoretical and experimental research on elements, assemblages, connection and material properties are considered for publication.